Re: SUO: 2000-7-26 example - nature of organisation
Chris,
Yes, I agree:
CP> We get traction (to use Mike Ushold's term) - the rubber hits the
road -
> when we look at "the structural relations that relate the parts". Without
> this, studying parts makes no sense. But this does not make trying to
> understand the general structure that parts can have useless, does it - I
> presume you were not suggesting that. If there is some general organizing
> structure, this is useful to know.
I agree that the notion of part is useful, but it is quite high
(i.e., general) in my hierarchy of roles. That means that it has
so many subtypes that anything interesting you might want to say
is really in the details.
As I said in my KR book, mereology is useful for many purposes,
such as representing plurals in natural languages or representing
physical collections without getting hung up about the difference
between subtypes and members. But when you want to do anything
serious, you have to get into the details.
That is also my criticism of modal mereology, which tries to talk
about the essence of something that makes it "necessary" or "possible"
for something to be a part. As I have said many times before, those
modal operators can be more meaningfully represented by looking at
the reasons (i.e., the laws) that require or permit something to be
true. A modal operator that says something is "necessary" without
stating the law or reason why it is necessary is a "cop out".
Bottom line: Look at the propositions and relations that link
parts or make something necessary or possible. Mereology is so
perfectly general that it doesn't really get to the heart of the
matter.
John Sowa